U.S. patent number 10,755,822 [Application Number 15/612,743] was granted by the patent office on 2020-08-25 for in-vessel rod handling systems.
This patent grant is currently assigned to TerraPower, LLC. The grantee listed for this patent is TerraPower, LLC. Invention is credited to Peter W. Gibbons, Stephen W. Hiller, Calen Kaneko, Owen Dean Nelson, Ashok Odedra, P. Harley Park.
![](/patent/grant/10755822/US10755822-20200825-D00000.png)
![](/patent/grant/10755822/US10755822-20200825-D00001.png)
![](/patent/grant/10755822/US10755822-20200825-D00002.png)
![](/patent/grant/10755822/US10755822-20200825-D00003.png)
![](/patent/grant/10755822/US10755822-20200825-D00004.png)
![](/patent/grant/10755822/US10755822-20200825-D00005.png)
![](/patent/grant/10755822/US10755822-20200825-D00006.png)
![](/patent/grant/10755822/US10755822-20200825-D00007.png)
![](/patent/grant/10755822/US10755822-20200825-D00008.png)
![](/patent/grant/10755822/US10755822-20200825-D00009.png)
![](/patent/grant/10755822/US10755822-20200825-D00010.png)
United States Patent |
10,755,822 |
Gibbons , et al. |
August 25, 2020 |
In-vessel rod handling systems
Abstract
A rod transfer assembly has an outer rotating plug. A pick-up
arm assembly extends from the outer rotating plug and includes a
pivoting arm. An inner rotating plug is disposed off-center from
and within the outer rotating plug and is rotatable independent of
a rotation of the outer rotating plug. An access port rotating plug
is disposed off-center from and within the inner rotating plug and
is rotatable independent of rotation of the outer and inner
rotating plugs. A pull arm extends from the access port rotating
plug.
Inventors: |
Gibbons; Peter W. (Kennewick,
WA), Hiller; Stephen W. (Kennewick, WA), Kaneko;
Calen (Seattle, WA), Nelson; Owen Dean (Richland,
WA), Odedra; Ashok (Bellevue, WA), Park; P. Harley
(Bellevue, WA) |
Applicant: |
Name |
City |
State |
Country |
Type |
TerraPower, LLC |
Bellevue |
WA |
US |
|
|
Assignee: |
TerraPower, LLC (Bellevue,
WA)
|
Family
ID: |
61243330 |
Appl.
No.: |
15/612,743 |
Filed: |
June 2, 2017 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20180061511 A1 |
Mar 1, 2018 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
62382650 |
Sep 1, 2016 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G21C
19/205 (20130101); G21C 19/50 (20130101); G21C
19/07 (20130101); G21C 17/042 (20130101); G21C
7/32 (20130101); G21C 19/065 (20130101); G21C
1/026 (20130101); G21C 7/10 (20130101); Y02E
30/30 (20130101); G21C 7/34 (20130101); G21C
7/08 (20130101) |
Current International
Class: |
G21C
19/00 (20060101); G21C 19/07 (20060101); G21C
7/32 (20060101); G21C 1/02 (20060101); G21C
19/06 (20060101); G21C 19/20 (20060101); G21C
7/10 (20060101); G21C 17/04 (20060101); G21C
19/50 (20060101); G21C 7/08 (20060101); G21C
7/34 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Hahn et al., "Conceptual Design of the Sodium-Cooled Fast Reactor
Kalimer-600" Nuclear Engineering and Technology 39(3) (Jun. 2007).
cited by applicant .
Yoo et al., "Overall System Description and Safety Characteristics
of Prototype Gen IV Sodium Cooled Fast Reactor in Korea" Nuclear
Engineering and Technology (Aug. 2016)
http://dx.doi.org/10.1016/j.net.2016.08.004. cited by applicant
.
Forsberg et al., Refueling Options and Considerations for
Liquid-Salt-Cooled Very High-Temperature Reactors, ORNL/TM-2006/92,
Jun. 2006. cited by applicant.
|
Primary Examiner: O'Connor; Marshall P
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Patent
Application No. 62/382,650, filed Sep. 1, 2016, entitled "IN-VESSEL
ROD HANDLING SYSTEM", the disclosure of which is hereby
incorporated by reference in its entirety herein.
Claims
We claim:
1. A rod transfer assembly, comprising: an outer rotating plug
comprising an outer rotating plug axis; a pick-up arm assembly
extending from the outer rotating plug and comprising a shaft
having a shaft axis parallel to the outer rotating plug axis and a
pivoting arm pivotable about the shaft axis and comprising a
pick-up mechanism having a pick-up axis disposed proximate an end
opposite the shaft of the pick-up arm, wherein the shaft axis is
positioned a first radial distance from the outer rotating plug
axis; an inner rotating plug disposed off-center from and within
the outer rotating plug, the inner rotating plug comprising an
inner rotating plug axis, wherein the inner rotating plug is
rotatable independent of a rotation of the outer rotating plug; an
access port rotating plug disposed off-center from and within the
inner rotating plug, wherein the access port rotating plug is
rotatable independent of a rotation of the outer rotating plug and
the inner rotating plug; and a pull arm extending from the access
port rotating plug and comprising a pull arm axis.
2. The rod transfer assembly of claim 1, wherein each of the outer
rotating plug axis, the shaft axis, the inner rotating plug axis,
and the pull arm axis are parallel to each other.
3. The rod transfer assembly of claim 2, wherein rotation of the
access port rotating plug and rotation of the inner rotating plug
aligns the pull arm axis with the outer rotating plug axis.
4. The rod transfer assembly of claim 1, wherein the outer rotating
plug, the inner rotating plug, and the access port rotating plug
are positionable so as to position the pull arm at a first distance
from an outer circumference of the large rotating plug.
5. The rod transfer assembly of claim 4, wherein upon pivoting of
the pivoting arm, the pick-up axis is positionable between the
shaft axis and the outer rotating plug axis; wherein when so
positioned, the pick-up axis is disposed a second distance from an
outer circumference of the outer rotating plug; and wherein the
second distance is at least one of greater than or equal to the
first distance.
6. The rod transfer assembly of claim 1, wherein each of the outer
rotating plug, the inner rotating plug, the access port rotating
plug, and the pivoting arm comprise a range of rotation at least 90
degrees.
7. The rod transfer assembly of claim 6, wherein the range of
rotation is at least 180 degrees.
8. The rod transfer assembly of claim 7, wherein the range of
rotation is substantially equal to 360 degrees.
9. The rod transfer assembly of claim 1, wherein the pull arm
extends above and below an upper surface of the inner rotating
plug.
10. The rod transfer assembly of claim 1, wherein a radius of
pivoting for the pivoting arm is less than a reference diameter of
the inner rotating plug.
11. The rod transfer assembly of claim 10, wherein the radius of
pivoting for the pivoting arm includes an entirety of an in-vessel
storage and a portion of a reactor core center.
12. The rod transfer assembly of claim 11, wherein a radius of
pivoting for the pull arm includes an entirety of a reactor core
center.
13. The rod transfer assembly of claim 12, wherein the radius of
pivoting for the pull arm includes an inner ring of an in-vessel
storage.
14. A rod transfer assembly, comprising: an outer rotating plug
comprising an outer rotating plug axis; a pick-up arm assembly
extending from the outer rotating plug and comprising a shaft
having a shaft axis parallel to the outer rotating plug axis and a
pivoting arm pivotable about the shaft axis, wherein the shaft axis
is positioned a first radial distance from the outer rotating plug
axis; an inner rotating plug disposed off-center from and within
the outer rotating plug, the inner rotating plug comprising an
inner rotating plug axis, wherein the inner rotating plug is
rotatable independent of a rotation of the outer rotating plug, and
wherein a radius of pivoting for the pivoting arm is less than a
reference diameter of the inner rotating plug; an access port
rotating plug disposed off-center from and within the inner
rotating plug, wherein the access port rotating plug is rotatable
independent of a rotation of the outer rotating plug and the inner
rotating plug; and a pull arm extending from the access port
rotating plug and comprising a pull arm axis.
15. The rod transfer assembly of claim 14, wherein the radius of
pivoting for the pivoting arm includes an entirety of an in-vessel
storage and a portion of a reactor core center.
16. The rod transfer assembly of claim 15, wherein a radius of
pivoting for the pull arm includes an entirety of a reactor core
center.
17. The rod transfer assembly of claim 16, wherein the radius of
pivoting for the pull arm includes an inner ring of an in-vessel
storage.
18. The rod transfer assembly of claim 14, wherein each of the
outer rotating plug, the inner rotating plug, the access port
rotating plug, and the pivoting arm comprise a range of rotation at
least 90 degrees.
19. The rod transfer assembly of claim 18, wherein the range of
rotation is at least 180 degrees.
20. The rod transfer assembly of claim 19, wherein the range of
rotation is substantially equal to 360 degrees.
Description
INTRODUCTION
Nuclear fission reactors include breed-and-burn fast reactors (also
referred to as traveling wave reactors, or TWRs). TWR means a
reactor that would be designed to operate indefinitely using
natural uranium, depleted uranium, spent light water reactor fuel,
or thorium as a reload fuel after start up, and in which waves that
breed and then burn would travel relative to the fuel. Thus, in
some aspects, the TWR is a once-through fast reactor that runs on
subcritical reload fuel which is bred up to a useful state and
burned in situ. In a TWR, a wave of breeding and fissioning (a
"breed-burn wave") is originated in a central core of the reactor
and moves relative to the fuel. In cases where the fuel is
stationary, the breed and burn wave expands outward from the
ignition point. In some cases, the fuel may be moved so that the
breed and burn wave stays stationary relative to the core (e.g., a
standing wave) but moves relative to the fuel; a standing wave is
to be considered a type of TWR. Movement of fuel assemblies is
referred to as "fuel shuffling" and can accomplish the standing
wave, adjustment to reactor characteristics (heat, flux, power,
fuel burn up, etc.). The central core in which the fuel assemblies
are shuffled is disposed in a reactor vessel. The fuel assemblies
include fissile nuclear fuel assemblies and fertile nuclear fuel
assemblies. Reactivity control assemblies may also be disposed in
the central core for adjustment of reactor characteristics.
Fission energy defined by the standing wave creates thermal energy
which is transferred in series through one or more primary coolant
loops and intermediate coolant loops to steam generators to produce
electricity, and low temperature heat is rejected through a set of
water-cooled vacuum condensers. The separation of coolant systems
into both primary and intermediate coolant loops helps maintain the
integrity of the core and the primary coolant loops. In the TWR,
both the primary and intermediate coolant loops utilize liquid
sodium as the coolant.
SUMMARY
In one aspect, the technology relates to a rod transfer assembly,
having: an outer rotating plug having an outer rotating plug axis;
a pick-up arm assembly extending from the outer rotating plug and
having a shaft having a shaft axis parallel to the outer rotating
plug axis and a pivoting arm pivotable about the shaft axis,
wherein the shaft axis is positioned a first radial distance from
the outer rotating plug axis; an inner rotating plug disposed
off-center from and within the outer rotating plug, the inner
rotating plug includes an inner rotating plug axis, wherein the
inner rotating plug is rotatable independent of a rotation of the
outer rotating plug; an access port rotating plug disposed
off-center from and within the inner rotating plug, wherein the
access port rotating plug is rotatable independent of a rotation of
the outer rotating plug and the inner rotating plug; and a pull arm
extending from the access port rotating plug and includes a pull
arm axis. In an embodiment, each of the outer rotating plug axis,
the shaft axis, the inner rotating plug axis, and the pull arm axis
are parallel to each other. In another embodiment, rotation of the
access port rotating plug and rotation of the inner rotating plug
aligns the pull arm axis with the outer rotating plug axis. In yet
another embodiment, the outer rotating plug, the inner rotating
plug, and the access port rotating plug are positionable so as to
position the pull arm at a first distance from an outer
circumference of the large rotating plug. In still another
embodiment, the pivoting arm includes a pick-up mechanism having a
pick-up axis disposed proximate an end opposite the shaft of the
pivoting arm.
In another embodiment of the above aspect, upon pivoting of the
pivoting arm, the pick-up axis is positionable between the shaft
axis and the outer rotating plug axis; wherein when so positioned,
the pick-up axis is disposed a second distance from an outer
circumference of the outer rotating plug; and wherein the second
distance is at least one of greater than or equal to the first
distance. In an embodiment, each of the outer rotating plug, the
inner rotating plug, the access port rotating plug, and the
pivoting arm have a range of rotation at least 90 degrees. In
another embodiment, the range of rotation is at least 180 degrees.
In yet another embodiment, the range of rotation is substantially
equal to 360 degrees. In still another embodiment, the pull arm
extends above and below an upper surface of the inner rotating
plug.
In another embodiment of the above aspect, a radius of pivoting for
the pivoting arm is less than a reference diameter of the inner
rotating plug. In an embodiment, the radius of pivoting for the
pivoting arm includes an entirety of an in-vessel storage and a
portion of a reactor core center. In another embodiment, a radius
of pivoting for the pull arm includes an entirety of a reactor core
center. In yet another embodiment, the radius of pivoting for the
pull arm includes an inner ring of an in-vessel storage. In still
another embodiment, the radius of pivoting for the pull arm
includes an outer ring of an in-vessel storage.
BRIEF DESCRIPTION OF THE DRAWINGS
The following drawing figures, which form a part of this
application, are illustrative of described technology and are not
meant to limit the scope of the technology as claimed in any
manner, which scope shall be based on the claims appended
hereto.
FIG. 1 illustrates, in a block diagram form, some of the basic
components of a molten fuel reactor.
FIG. 2 is a perspective view of an example in-vessel rod handling
system.
FIGS. 3A-3H are top plan views of components of the in-vessel rod
handling system shown in FIG. 2 in various relative positions.
DETAILED DESCRIPTION
FIG. 1 illustrates, in a block diagram form, some of the basic
components of a travelling wave reactor (TWR) 100. In general, the
TWR 100 includes a reactor core 102 containing a plurality of fuel
assemblies (not shown). The core 102 is disposed at the lowest
position within a pool 104 holding a volume of liquid sodium
coolant 106. The pool 104 is referred to as a hot pool and has a
sodium temperature higher than that of a surrounding cold pool 108
(due to the energy generated by the fuel assemblies in the reactor
core 102), which also contains liquid sodium coolant 106. The hot
pool 104 is separated from the cold pool 108 by an inner vessel
110. A headspace 112 above the level of the sodium coolant 106 may
be filled with an inert cover gas, such as argon. A containment
vessel 114 surrounds the reactor core 102, hot pool 104, and cold
pool 108, and is sealed with a reactor head 116. The reactor head
116 provides various access points into the interior of the
containment vessel 114.
The size of the reactor core 102 is selected based on a number of
factors, including the characteristics of the fuel, desired power
generation, available reactor 100 space, and so on. Various
embodiments of a TWR may be used in low power (around 300
MW.sub.e--around 500 MW.sub.e), medium power (around 500
MW.sub.e--around 1000 MW.sub.e), and large power (around 1000
MW.sub.e and above) applications, as required or desired. The
performance of the reactor 100 may be improved by providing one or
more reflectors, not shown, around the core 102 to reflect neutrons
back into the core 102. Additionally, fertile and fissile nuclear
assemblies are moved (or "shuffled") within and about the core 102
to control the nuclear reaction occurring therein. Components for
moving these nuclear assemblies within the core are the subject of
this application and are described in more detail below in FIGS.
2-3H.
The sodium coolant 106 is circulated within the vessel 114 via a
primary sodium coolant pump 118. The primary coolant pump 118 draws
sodium coolant 106 from the cold pool 108 and injects it into the
hot pool 104, proximate (e.g., below) the reactor core 102, where
the coolant 106 is heated due to the reactions taking place within
the reactor core 102. A portion of the heated coolant 106 enters an
intermediate heat exchanger 120 from an upper portion of the hot
pool 104, and exits the intermediate heat exchanger 120 at a
location in the cold pool 108. This primary coolant loop 122 thus
circulates sodium coolant 106 entirely within the reactor vessel
114.
The intermediate heat exchanger 120 also includes liquid sodium
coolant and acts as a barrier between the primary coolant loop 122
and a power generation system 123, so the integrity of the core 102
and primary coolant loop 122 can be ensured. The intermediate heat
exchanger 120 transfers heat from the primary coolant loop 122
(fully contained within the vessel 114) to an intermediate coolant
loop 124 (that is only partially located within the vessel 114).
The intermediate heat exchanger 120 passes through an opening in
the inner vessel 110, thus bridging the hot pool 104 and the cold
pool 108 (so as to allow flow of sodium 106 in the primary coolant
loop 122 therebetween). In an embodiment, four intermediate heat
exchangers 120 are distributed within the vessel 114.
The intermediate coolant loop 124 circulates sodium coolant 126
that passes through pipes into and out of the vessel 114, via the
reactor head 116. An intermediate sodium pump 128 located outside
of the reactor vessel 114 circulates the sodium coolant 126. Heat
is transferred from the sodium coolant 106 of the primary coolant
loop 122 to the sodium coolant 126 of the intermediate coolant loop
124 in the intermediate heat exchanger 120. The sodium coolant 126
of the intermediate coolant loop 124 passes through a plurality of
tubes 130 within the intermediate heat exchanger 120. These tubes
130 keep separate the sodium coolant 106 of the primary coolant
loop 122 from the sodium coolant 126 of the intermediate coolant
loop 124, while transferring heat energy therebetween.
A direct heat exchanger 132 extends into the hot pool 104 and
provides additional cooling to the sodium coolant 106 within the
primary coolant loop 122. The direct heat exchanger 132 is
configured to allow sodium coolant 106 to enter and exit the heat
exchanger 132 from the hot pool 104. The direct heat exchanger 132
has a similar construction to the intermediate heat exchanger 120,
where tubes 134 keep separate the sodium coolant 106 of the primary
coolant loop 122 from a sodium coolant 136 of a direct reactor
coolant loop 138, while transferring heat energy therebetween.
Other ancillary reactor components (both within and outside of the
reactor vessel 114) include, but are not limited to, pumps, check
valves, shutoff valves, flanges, drain tanks, etc., that are not
depicted but would be apparent to a person of skill in the art.
Additional penetrations through the reactor head 116 (e.g., a port
for the primary coolant pump 118, inert cover gas and inspection
ports, sodium processing ports, etc.) are not depicted. A control
system 140 is utilized to control and monitor the various
components of the reactor 100.
Broadly speaking, this disclosure describes configurations that
improve the performance of the reactor 100 described in FIG. 1.
Specifically, embodiments, configurations, and arrangements of an
in-vessel rod transfer assembly are shown and described in more
detail below with reference to FIGS. 2-3H.
In general, the in-vessel rod handling assembly allows for movement
of fuel assemblies within and proximate the core without having to
open the vessel, thus enabling more efficient operation of the
reactor. For example, the in-vessel rod handling assembly manages
the locations of the various fuel assemblies within the vessel,
namely, by moving fuel assemblies between and within the core and
the storage areas of the vessel. Such movement or "shuffling" of
fuel assemblies is required so as to control the nuclear reaction
occurring in the vessel. The in-vessel rod handling assembly also
facilities movement of fuel assemblies into an out of the reactor
vessel (via one or more penetrations in the reactor head). Such
movement into and out of the reactor vessel is required as new fuel
is introduced to the vessel and spent fuel is removed from the
vessel.
The shuffling of the fissile and fertile nuclear fuel assemblies
occurs entirely within the vessel and beneath the reactor head.
This configuration thereby limits the need to open the reactor,
which maintains the shielding of the vessel for any heated and/or
radioactive materials therein. The in-vessel rod handling assembly
moves fuel assemblies to and from in-vessel storage sites or tubes
at the periphery of the core to various locations within the core.
Additionally, the in-vessel rod handling assembly moves fuel
assemblies between various locations within the core area.
Moreover, fuel assemblies introduced to the vessel are moved from a
transfer pot to the periphery of the core or the core itself.
Reverse operation into the transfer pot allows fuel assemblies to
be removed from the vessel. All of these operations and movements
occur without having to open up the vessel, thereby increasing
reactor efficiency.
FIG. 2 is a perspective view of an example embodiment of an
in-vessel handling system 200 and core assembly 202. The in-vessel
handling system 200 includes an outer rotating plug 204 with a
pick-up arm assembly 210 secured thereto, an inner rotating plug
206 (shown removed from FIG. 2), and an access port rotating plug
208 with a pull arm 212 secured thereto. The core assembly 202 is
schematically shown and includes a central core region 214 having a
plurality of fissile nuclear fuel assemblies 215 and fertile
nuclear fuel assemblies 217, a peripheral core region 216 including
in-vessel storage pots 218, and fuel transfer port 220. In FIG. 2
and the following figures, only a portion of the fissile nuclear
fuel assemblies 215, fertile nuclear fuel assemblies 217, and
in-vessel storage pots 218 are depicted for illustrative purposes.
In the embodiment shown, the outer rotating plug 204, inner
rotating plug 206, and access port rotating plug 208 are all
vertically spaced apart from the top 228 of the central core region
214. Many components are omitted for clarity and other embodiments
can include more or fewer components of the in-vessel handling
system 200 and/or core assembly 202.
The outer rotating plug 204 rotates about central axis A with a
typical rotation range of +/-180 degrees. In other examples, the
range of rotation may extend to +/-360 degrees. Typically, the
reactor head 116 depicted in FIG. 1 surrounds the outer rotating
plug 204.
The pick-up arm assembly 210 is secured to the outer rotating plug
204 at a position radially off-center from the central axis A and
rotates with the outer rotating plug 204. The pick-up arm assembly
210 includes a shaft 222 with shaft axis SA, where the shaft axis
SA is parallel to the central axis A of the outer rotating plug
204. The pick-up arm assembly 210 extends through the outer
rotating plug 204 to the top of the reactor core 228. The pick-up
arm assembly 210 also includes a pivoting arm 224 having a pick-up
axis PU. The pivoting arm 224 pivots about the shaft axis SA
independent of the rotation of the outer rotating plug 204. In
examples, the pivoting arm 224 has a typical rotation range of
+/-180 degrees, but in other instances, pivoting arm 224 may be
rotated continuously in either direction.
The inner rotating plug 206 is positioned within the outer rotating
plug 204. The inner rotating plug 206 has a central axis B that is
radially offset from the central axis A of the outer rotating plug
204. Additionally, the inner rotating plug 206 is rotatable
independent of the outer rotating plug 204. The inner rotating plug
206 has a typical rotation range of +/-90 degrees, but in other
examples, the rotation range may extend to +/-360 degrees.
The access port rotating plug 208 is positioned within the inner
rotating plug 206. The access port rotating plug 208 has a central
axis C that is offset, radially, from both the outer rotating plug
204 central axis A and the inner rotating plug 206 central axis B.
The access port rotating plug 208 has a typical rotation range of
+/-90 degrees, but in other examples, the rotation range may extend
to +/-360 degrees.
The pull arm 212 is supported by the access port rotating plug 208
and is rotated by the access port rotating plug 208. The pull arm
has an axis PA that is offset from each of: the outer rotating plug
204 central axis A, the inner rotating plug 206 central axis B, and
the access port rotating plug 208 central axis C. The pull arm 212
extends through the access port rotating plug 208 down to the top
of the reactor core 228.
Generally, the in-vessel handling system 200 is configured to
shuffle the fissile nuclear fuel assemblies 215 and fertile nuclear
fuel assemblies 217 between the central core region 214 and the
peripheral core region 216. This is performed at various stages of
core life as required or desired to initiate, maintain, accelerate,
or terminate nuclear reactions or power generation and/or for
safety reasons. The in-vessel handling system 200 permits movement
of the fissile nuclear fuel assemblies 215 and/or fertile nuclear
fuel assemblies 217 without removing those assemblies from the
nuclear reactor 100.
Lower ends of the pick-up arm assembly 210 and the pull arm 212
include suitable gripping devices, such as grapples or the like,
that enable gripping of selected fissile nuclear fuel assemblies
215 and/or fertile nuclear fuel assemblies 217 during movement
operations. Rotation of the rotating plugs 204, 206, and 208, and
the pivoting arm 224, allows the pick-up arm assembly 210 and the
pull arm 212 to be localized to any desired position for pulling a
selected fuel assembly out of the core 214 at any desired location,
including a location in the peripheral core region 216. The
selected fuel assembly may then be moved to a different location
within the core 214, peripheral core region 216, or fuel transfer
port 220.
FIGS. 3A-3H are top plan views of the in-vessel handling system 200
and central core region 214, with the inner rotating plug 206
omitted for clarity. Each of FIGS. 3A-3H is discussed concurrently
below, unless otherwise noted. For ease of discussion only the
position of the components in FIGS. 3A-3H will be discussed using
cardinal directions (North, South, East, West). For clarity, FIGS.
3A-3H omit many fuel assemblies that would be positioned within the
central core region 214. Similarly, many in-vessel storage pots 218
are omitted, again for clarity.
FIGS. 3A-3H depict various ranges of motions, and various relative
positions, of the components shown in FIG. 2. Internal structures
disposed between the plugs 204, 206 and core assembly 202, not
shown in FIG. 2, may prevent or limit all ranges of motion depicted
in FIGS. 3A-3H. These internal structures may require different
positioning of one or both plugs 204, 206 to access the locations
in core assembly 202 as shown.
The peripheral core region 216 includes three concentric rings of
in-vessel storage pots 218. FIGS. 3A-3B show the pull arm 212 at
its outer-most reach, which coincides with the innermost ring of
storage pots 218. In other instances, the pull arm 212 is
configured to be able to reach every ring of storage pots 218,
including the outermost ring. To achieve this orientation, the
inner rotating plug 206 and access port rotating plug 208 are
rotated such that the position of the pull arm 212 in the East
direction is maximized. To enable the pull arm 212 to reach other
in-vessel storage pots 218 within the inner most ring, the outer
rotating plug 204 rotates with the inner rotating plug 206 and
access port rotating plug 208 remaining relatively stationary. By
the cooperative rotation of the outer rotating plug 204, the inner
rotating plug 206, and the access port rotating plug 208, the pull
arm 212 radius of pivoting includes the entirety of the central
core 214.
In FIGS. 3A-3B, the pull arm 212 is positioned a distance D1 from
an outer circumference 230 of the outer rotating plug 204. The
orientation shown in FIG. 3A is the minimum value of D1. As the
inner rotating plug 206 and/or the access port rotating plug 208
rotate in either direction, D1 changes. D1 reaches a maximum when
the pull arm 212 is positioned as depicted in FIG. 3C.
As shown in FIG. 3A, the pick-up arm assembly 224 may pivot along
pivot radius R such that the pick-up axis PU is over the outer
portion of the core 214. In this configuration, the pick-up axis PU
is between the shaft axis SA and the outer rotating plug 204 axis A
along line l. Additionally, the pick-up axis PU is disposed a
distance D2 from the outer circumference 230 of the outer rotating
plug 204. Distance D2 is equal to or greater than distance D1, when
distance D1 is at a minimum.
FIG. 3B shows an orientation where, from the orientation in FIG.
3A, the outer rotating plug 204 has rotated 90 degrees clockwise,
the inner rotating plug 206 has rotated 180 degrees, and the access
port rotating plug 208 has rotated 180 degrees. FIG. 3B shows the
pull arm 212 oriented such that it may reach the center of the core
214. Put another way, the access port rotating plug 208 and the
inner rotating plug 206 have rotated such that the pull arm axis
212 PA aligns with the outer rotating plug 204 axis A. Any rotation
of the outer rotating plug 204 from the position shown in FIG. 3B
would not change the position of the pull arm 212 axis PA.
FIG. 3C shows the pull arm 212 oriented such that it may reach an
inner row of storage pots 218. To achieve the orientation shown in
FIG. 3C, the outer rotating plug 204 has rotated 180 degrees from
its position in FIG. 3A.
FIG. 3D shows the pull arm 212 positioned at a random location over
the core 214. Relative to the orientation shown in FIG. 3C, outer
rotating plug 204 has rotated 90 degrees clockwise and both inner
rotating plug 206 and access port rotating plug 208 have rotated.
This figure helps illustrate that via rotation of the outer
rotating plug 204, the inner rotating plug 206, and the access port
rotating plug 208, the pull arm 212 can be positioned at virtually
any location over the core 214 and the inner ring of the peripheral
core region 216.
FIG. 3E shows the outer rotating plug 204 rotated such that the
pick-up arm assembly 210 can reach the fuel transfer port 220. As
shown, the pivoting arm 224 has pivoted to be positioned over the
fuel transfer port 220. In the position shown in FIG. 3E, a core
fuel assembly rod may be accessible to the pull arm 212. After the
outer rotating plug 204 has rotated into the position shown in FIG.
3E, the pivoting arm 224 pivots until a grapple portion is
positioned over the fuel transfer port 220.
FIGS. 3F-3G show the outer rotating plug 204, the inner rotating
plug 206, and the access port rotating plug 208 in random
orientations, and the pick-up arm assembly 210 in position above an
in-vessel storage pot 218. Generally, the pivoting arm 224 of the
pick-up arm assembly 210 can be positioned over each concentric row
of the in-vessel storage pots 218. As shown in FIG. 3F, the
pivoting arm 224 is interacting with the inner-most ring of the
in-vessel storage pot 218 array. In FIG. 3G, the pivoting arm 224
is interacting with the middle ring of the in-vessel storage pot
218 array. The positioning of the inner rotating plug 206 and the
access port plug 208 do not affect the in-vessel storage pot 218
interactions.
FIG. 3H shows the pick-up arm assembly 210 in position above a
location in the core 214. Generally, the pivoting arm 224 can be
positioned over the outermost positions within the core 214. As
shown in FIG. 3H, the pivoting arm 224 is positioned over the outer
ring of the core 214.
It is to be understood that this disclosure is not limited to the
particular structures, process steps, or materials disclosed
herein, but is extended to equivalents thereof as would be
recognized by those ordinarily skilled in the relevant arts. It
should also be understood that terminology employed herein is used
for the purpose of describing particular embodiments only and is
not intended to be limiting. It must be noted that, as used in this
specification, the singular forms "a," "an," and "the" include
plural referents unless the context clearly dictates otherwise.
It will be clear that the systems and methods described herein are
well adapted to attain the ends and advantages mentioned as well as
those inherent therein. Those skilled in the art will recognize
that the methods and systems within this specification may be
implemented in many manners and as such is not to be limited by the
foregoing exemplified embodiments and examples. In this regard, any
number of the features of the different embodiments described
herein may be combined into one single embodiment and alternate
embodiments having fewer than or more than all of the features
herein described are possible.
While various embodiments have been described for purposes of this
disclosure, various changes and modifications may be made which are
well within the scope contemplated by the present disclosure.
Numerous other changes may be made which will readily suggest
themselves to those skilled in the art and which are encompassed in
the spirit of the disclosure.
* * * * *
References